Unit heater



w. J. HARTWIG April 30, 1946.

' UNIT HEATER Filed June 19, 1945 v 0 0 0 0 9 Q Q Q 1L9 941E999INVENTOR.

HTTOZNEVS.

Patented Apr. 30, 1946 UNIT HEATER Walter J. Hartwig, Wausau, Wis,assignor to D. J. v, Murray Manufacturing 00., Wausau, Wis., a

corporation of Wisconsin Application June 19, 1943, Serial No. 491,455 42 Claims.

My invention relates in general to improvements in the art of heattransfer, and relates more specifically to various improvements intheconstruction and operationof unit heaters or coolers especially of thetype wherein one or more fluid confining and circulating coils for theheating or coollng'medium are disposed about a central axis while air orgas which is to be heated or cooled is caused to flow either inwardly oroutwardly across the coils with the aid-of a fan or the like arrangedconcentrically of the central axis of the A primaryobject of thisinvention is to provide a new and useful heat transfer assemblage whichis both simple and compact in construction,

and which is also flexible in its adaptations and extremely efiicient inuse.

It has heretofore been proposed as shown in the co-pending applicationof Newe'nham A, Gray, Serial No. 489,905, filed June '7, 1943, toprovide a highly efiicientheat transfer section formed of a singlecasting with uniform elliptical cross-section at its elongated medialhollow portion and with transverse cylindrical chambers at its oppositeends each provided with a plurality of radially disposed bosses foreffecting varied connections between adjoining sections. These improvedheat transfer sections may be provided with external radiation pins inorder to increase their efliciencyyand may also be grouped bothlaterally and longitudinally for various heat transfer purposes; and inorder'to provide a fluid-tight connection between the adjoining sectionsit is preferable to utilize connectingnipples having right and left handexternal threads at their opposite ends coactingwith similar internalscrew threads formed in the adjoining bosses Or cylindricalchamberedend: portions of the adjacent sections. While suchoppositelythreaded nipples have heretofore-been utilized for similarpurposes, these prior connecting nipples wereordinarily provided withinternal projections or other internal means for effecting manipulationthereof; and since the nipples ordinarily serve as fluid conduits orconductors for connecting the interiorsof adjoining sections, suchinternal projections or manipulating means were very objectionable asbeing obstructive to the fluid flow and also being debris and dirtaccumulators.

It is therefore a mor specific object of my present invention toprovidean improved oppositely threaded connecting nipple for heattransfersections, which has a smooth and unobstructed' interior "whilealso being readily manipulable from within its' normal enclosure.

Another specific object of this invention is to provide a simplifiedright and left hand threaded nipple for quickly connecting various typesof heat transfer sections, which is conveniently manipulable from eitherend with the aid of a flat bar or spanner wrench, and the interior ofwhich is smoothly cylindrical, thus permitting the improved nipple to beformed from sections of ordinary pipe and at minimum cost.

A further specific object of the present invention is to provide animproved unit heater assemblage utilizing heat transfer sections of theabove described prior type, either in single or multiple coil formation,and which is extremely simple in construction and highly efficient inoperation.

Still another specific object of the invention is to provide a compactand durable unit heater comprising a central fan or blower and one ormore concentric heat transfer coils, which can be readily manufacturedin various sizes and at minimum cost, by utilizing interchangeablysimilar cast metal radiator sections.

These and other specific-objects and advantages of the improvement willbe apparent from the following detailed description.

A clear understanding of the several features constituting my presentinvention, and of the mode of constructing, assembling, and operatingunit heaters embodying these features, may be had by referring to thedrawing accompanying and forming a part of this specification in whichlike reference characters designate the same or similar parts in thevarious views.

Fig. l is a part sectional top or plan view of one of my improved unitheaters, portions having been broken away so as to reveal normallyconcealed structure; i

Fig. 2. is a part sectional side elevation of the unit heater, thesection, having been taken along aradial plane; i v

Fig. 3 is a perspective view of one of the improved comer brackets forspacing the housing plates of the unit; 7

Fig. 4 is an enlarged part-sectional side elevation of one of theimproved connecting nipples for the heat transfer units; and

Fig.- 5 is a fragment of the adjoining ends of several of the improvedheat transfer units, showing the method of stacking two or more of thecoils upon each other so as to increasethe capacity of the unit heater.

While the invention has been shown and described herein as' beingembodied in an electric motor driven down-blow unit heater utilizingheat transfer sections of the improved Gray type, it is not my desire orintent to thereby unnecessarily restrict the scope or utility of theimproved features some of which are more generally applicable to othertypes of unit heater assemblages.

Referring specifically to Figs. 1 to 4 inclusive of the drawing, theimproved unit heater shown therein comprises in general an endlessseries of interchangeably similar elongated hollow heat transfer unitsor sections 1 each having as shown in Fig. 1 a screw threaded centralend opening 8 I at one of its extreme ends and a lateral screw throughand prevent accumulation of debris threaded side opening 9 near itsopposite end; a series of externally threaded connecting nipples IIJeach connecting the end opening 8 of one section I with the side opening9 Man adjoining section I so as to provide an approximately square coilor continuous fluid conducting conduit ex tending around a centralupright axis; a series of resilient corner brackets I I sprung intoclamping engagement with the ends of the successive sections I; an upperhousing plate'l2 having a downwardly directed peripheral flange I3engagin the upper edges of all of the brackets II, and beingprovidedwith a central frusto-conical pocket or deflecting element I4; alower housing plate I5 having an upwardly directed peripheral flange I6engaging the lower edges of all of the brackets I I, and being providedwith a central tubular portion I1 disposed concentric with respect tothe element I4 and the central upright coil axis; an air circulating fanrotor I8 disposed within the tubular casing portion I1 and having itssupporting shaft I9 direct connected to an electric driving motor whichis mounted within the pocket element l4; and a series of casing orhousing clamping and suspension bolts 2I firmly uniting the plates I2,I5 adjacent to the corner bracket I I.

Each of the hollow heat transfer sections 7 comprises an elongated; bodyportion having elliptical transverse cross-section as shown in Fig. 2and being provided with a multiplicity of upwardly and downwardlyprojecting radiation pins 22, and a transverse approximately cylindricalhollow end chamber 23 formed integral with each end of the body andhaving several bosses 24 radiating therefrom. The threaded opening 8 ofeach section I is formed in one of these radiating bosses 24, while thethreaded opening, 9 is formed inan end of one of the chambers23; and thecasing plates I2, I5 coact with the flat outer faces of the upwardly anddownwardly extending bosses 24. Pipe plugs 25 may be utilized to closethe unused openings in the bosses 24, but one of these openings at onecorner of the coil may be utilized for connection with an inlet pipe 26while a diagonally opposite opening at another corner may be utilizedfor attachment to an exhaust pipe 21. Heating or cooling. fluid may thusbe passed through the coil from the pipe 26 to the pipe 21, and theradiation pins 22 project into the spaces between the body portions ofthe sections 1 and the housing plates I2, I5. The heat radiating unitsor sections 1 are preferably formed by casting and-areinterchangeablysimilar, and any desired number of the bosses 24 may be provided withtapped or threaded openings. v, I

The connecting nipples ID for uniting the several sections I into groupsor coil formation, are of improved construction as shown in detail inFig. 4. Each of these nipples IIl'is, of tubular shape having a smoothcylindrical internal central bore 28 and. external right and left handthreads 29 at the opposite ends thereof. Each of the extreme ends ofeach nipple III is provided with one or more sets of diametricallyopposite notches 30 adapted for the application of a flat plate orspanner wrench, and when these nipples are rotated in alined properlythreaded openings 8, 9, they will draw the adjacent sections 1 firmlyand snugly toward each other against an intervening gasket 3|. Thenipples I0, may be quickly produced from lengths of standard piping ortubing, and the smooth cylindrical interiors thereof avoid obstructionto flow of fluid theretherein.

The main casing or housing plates I2, I5 and the central flow deflectingelement I4 and corner brackets II, may all be formed of sheet metal withthe aid of punches and dies, and the brackets II are preferablyconstructed of resilient material and are of improved formation as shownin Fig. 3. Each of these corner brackets II has a set of semi-circularnotches 32 disposed approximately at right angles to each other andadapted to be sprung into clamping engagement with a boss 24 and acylindrical chamber portion 23 at the adjacent corner of the rectangularcoil, as clearly shown in Fig. 1; and when properly applied, no otherfastening means for the brackets II is required. The brackets II are ofsuch height, that they will cooperate with the upwardly and downwardlyextending bosses 24 so as to prop y space the plates I2, l5 apart; andthe flanges I3, I6 of these housing plates I2, I5 snugly engage theupper and lower edge portions of the brackets II so as to preventdisplacement of the housing relative to the central vertical axis of theunit heater. The suspension bolts 2| which clamp the plates I2, I5against the brackets I I and bosses 24, may also be provided with loopsor eyes as shown, in order to facilitate suspension or the assemblagefrom overhead structure.

The central frustro-conical pocket element I4 within which the fanpropelling motor 20 is seated and detachably mounted, also serves as adeflector for changing the direction of flow of the air or other gaswhich is drawn inwardly over the heat transfer coil, from radial toaxial, so 7 that this air will flow past the fan rotor I8 and throughthe tubular discharge portion I! in an axial direction. In someinstances, it may be desirable to also provide an inlet grille 33laterally adjacent to each heat transfer section I between the housingplates I2, I5, and these grilles 33 may be held in place between thesuccessive corner brackets II by means of the flanges I3, I6 of thecasing plates and by the clamping bolts 2 I. The outlet end of thetubular portion I! of the lower casing plate I5, may also be providedwith a whirl breaker 34 comprising a series of radial vanes, and if sodesired the fan rotor I8 may be steadied by contact with the central hubof the breaker 34. l 1

While one of the improved coil assemblages may be suflicient for mostunit heaters, it may in some instances be desirable to double or triplethe capacity of the unit, and this can readily be accomplished byutilizing two or more of the coils in series as shown in Fig. 5. Eachcoil assemblage is then composed of four of the heat transfer sections 1as in Figs. 1 and 2, but several of the coils are stacked or positionedconcentrically with respect to their common central axis, and areinterconnected by nipples I0 uniting the adjacent bosses'24 thereof.When such a group of coils is assembled in a unit heater,- it is onlyneces;

sary to lengthen the fan shaft is and to double or triple the verticallength or height of the brackets ii and grilles 33, depending upon thenumber of coils actually provided. In this manner, any desired number ofthe interchangeably similar heat transfer units 1 may be utilized toproduce unit heater assemblages of any desired capacity, and the housingplates I2, IE will remain the same regardless of the capacity of theheater assemblage.

During normal manufacture and use of the improved unit heaters, the coilassemblages and the corner brackets II and grilles 33 are firmly clampedbetween the upper and lower housing plates l2, IS with the aid of thecorner bolts 2|, and the assemblages may be suspended from overheadstructure by utilizing the eyes of these bolts, or they may be otherwisesupported in any suitable manner and in any desired position. If theunit is to be utilized as a heater, heating fluid should be passedthrough the coils from the inlet pipe 26 to the outlet pipe 21; and ifthe assemblage is to be employed for cooling purposes, cooling mediumwill be likewise passed through the coils. The motor 20 may then beplaced in operation so as to rotate the fan l8, thus causing the fanrotor to draw air or other ambient gas inwardly through the grilles 33and across the sections 1 between the pins 22 toward the central axis ofthe unit, thereby either heating or cooling the air or other gas. Afterhaving its temperature thus changed, the stream of entering air or gashas its direction of flow converted from radial to axial by thefrustro-conical deflector element 14, whereupon the finally conditionedstream is delivered axially through the tubular casing portion I! by therapidly revolving fan rotor [8. If it is desired to prevent swirling ofthe blast delivered from the unit, a Whirl-breaker 34 having fiat radialvanes may be utilized, but this breaker may either be omitted entirely,or it may be replaced by a flow regulator having pivotally adjustablevanes. It will thus be noted that the change in temperature of the airor other gas flowing through the unit is effected both automatically andefliciently by the coil sections 1 which have extremely extensiveradiating surface by virtue of their transverse elliptical cross-sectionand the provision of the pins 22, and that the unit for effecting suchoperation is exceedingly simple, durable, and compact.

From the foregoing detailed description it will be apparent that mypresent invention provides an improved unit heater or cooler assemblagewhich may be constructed and assembled at moderate cost by utilizing theinterchangeably similar heat transfer sections 1 and the improvednipples Ill, together with the improved corner brackets I I, so as toprovide an extremely eflicient and sturdy structure. The improvednipples l not only facilitate firm and leak-proof assembly or thestructure, but also insure open and unobstructed passages between theinterconnected hollow sections 1; and the formation of the brackets Hand casing plates l2, I provides a durable housing which can be quicklyand conveniently assembled or dismantled without the aid of an excessivenumber of bolts, screws or other fastening devices. The grilles 33 andwhirl-breakers 34 may or may not be used, and

the fluid supply and exhaust pipes 26, 2! may be connected to the coilsin any desired manner which will insure most efiicient distribution ofthe 6 heat transfer fluid. While the improved unit heater has been shownin vertical position, it may obviously be disposed either vertically,horizontally, or in any other desired position, and the assemblage mayalso be utilized for cooling as well as heating purposes. The units mayalso be readily produced in various sizes having any desired heattransfer capacity, and the assemblages are obviously of extremely neatappearance and of exceedingly compact construction.

It should be understood that it is not desired to limit the invention tothe exact details of construction, or to the precise mode of use, hereinshown and described, for various modifications within the scope of theappended claims may occur to persons skilled in the art.

Iclaim:

1. A heating assemblage comprising, an endless series of elongatedsimilar heat transfer sections each having a set of bosses at each ofits opposite ends, each set of said bosses consisting of one boss thecentral axis of which is disposed longitudinally of the section and apair of other bosses the common axis of which is dis- 3 posedtransversely of the section, conduit means connecting one longitudinalboss of each section with a transverse boss of an adjoining section, a

corner bracket having notches resiliently frictionally engaging two ofthe bosses at one end 35 of each section, an elongated grille extendingalong each section and spanning the space between the adjacent brackets,enclosing plates coacting with the opposite sides of all of said grillesand brackets to provide a confining casing for the series having anoutlet extending transversely of the latter, and means for circulatingair through said grilles and over said heat transfer sections and out ofsaid outlet.

2. A heating assemblage comprising, an endless series of elongatedsimilar heat transfer sections each having a set of bosses at each ofits opposite ends, each set of said bosses consisting of one boss thecentral axis of which is disposed longitudinally of the section and apair 59 of other bosses the common axis of which is disposedtransversely of the section, conduit means connecting one longitudinalboss of each section with a transverse boss of an adjoining section, a

corner bracket having notches resiliently frictionally engaging two ofthe bosses at one end of each section, an elongated grille extendingalong each section and spanning the space between th adjacent brackets,enclosing plates coacting with the opposite sides of all of said grillesand 0 brackets to provide a confining casing for the series having anoutlet extending transversely of the latter, said plates havingperipheral flanges externally engaging said brackets and said grilles toprevent displacement of the plates and of the grilles, and means forcirculating air through said grilles and over said heat transfersections and out of said outlet.

WALTER J. HARTWIG.

